The reliability of self-reported home values in a developing country context

We analyze the reliability of homeowners¿ estimates of the value of their houses, in a household survey (of poor suburbs) of a developing country. We show that non-response to the home value question by the owner is uncorrelated with the appraised value of the house and other demographic characteristics of the respondent. We also document that homeowners with long tenure largely overestimate the value of their home. Moreover, both the bias and the lack of precision in homeowners¿ estimates are correlated with tenure, but not with socioeconomic characteristics. However, we also show that self-reported home values from short-tenure homeowners can be used to obtain unbiased and precise estimates of the average house value at the census tract level.bias, inaccuracy, housing prices, owners¿ estimates, appraised values.

Predators do not spill over from forest fragments to maize fields in a landscape mosaic in central Argentina

South America is undergoing a rapid and large scale conversion of natural habitats to cultivated land. Ecosystem services (ESs) still remain important but their level and sustainability are not known. We quantified predation intensity in an Argentinian agricultural landscape containing remnants of the original chaco serrano forest by using artificial sentinel prey. We sought to identify the main predators, and the effect of landscape configuration and maize phenology on predation pressure by invertebrate and vertebrate predators in this landscape. The most common predators were chewing insects (50.4% predation events), birds (22.7%), and ants (17.5%). Overall predation rates in forest fragments (41.6% d-1) were significantly higher than in the surrounding maize fields (21.5% d-1). Invertebrate predation was higher inside and at the edge of forest fragments than within fields, and did not change with increasing distance from a fragment edge, indicating a lack of spillover from the native habitat remnants to the cultivated matrix at the local scale. Distance from a continuous forest had a positive impact on predation by invertebrates and a negative impact on vertebrate predation.Fil: Ferrante, Marco. Aarhus University. Flakkebjerg Research Centre. Department of Agroecology; DinamarcaFil: González, Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Gabor L., Lovei. Aarhus University. Flakkebjerg Research Centre. Department of Agroecology; Dinamarc

Impacts of Radar Echoes on Internal Calibration Signals in the TerraSAR-X Instrument

For calibrating and monitoring the required radiometric stability, the radar instrument of TerraSAR-X features an internal calibration facility coupling into an additional port of the TRMs. Calibration pulses are routed through the front-end to characterise critical elements and parameters of the transmit (TX) and receive (RX) path. Changes in the signal path appear due to thermal effects, degradation, or extreme conditions in space. Especially the front-end TRMs controlling the phased array antenna are of crucial significance for the instrument reliability. There are many indications that the interference of the RX-Calibration signals is caused by an echo from a transmitted TerraSAR-X chirp pulse of the same data take. As consequently implemented in the TerraSAR-X system, different approaches solve these effects of signal interference. In orbit, the commanding sequence can be optimised for avoiding interference. At processing level, averaging techniques minimise the noise effects inside the calibration signals. This paper presents the effects of the radar echoes on the whole internal calibration process and how they can be detected and minimised

A new survey of cool supergiants in the Magellanic Clouds

In this study, we conduct a pilot program aimed at the red supergiant population of the Magellanic Clouds. We intend to extend the current known sample to the unexplored low end of the brightness distribution of these stars, building a more representative dataset with which to extrapolate their behaviour to other Galactic and extra-galactic environments. We select candidates using only near infrared photometry, and with medium resolution multi-object spectroscopy, we perform spectral classification and derive their line-of-sight velocities, confirming the nature of the candidates and their membership to the clouds. Around two hundred new RSGs have been detected, hinting at a yet to be observed large population. Using near and mid infrared photometry we study the brightness distribution of these stars, the onset of mass-loss and the effect of dust in their atmospheres. Based on this sample, new a priori classification criteria are investigated, combining mid and near infrared photometry to improve the observational efficiency of similar programs as this.Comment: 39 pages, 10 figures. Accepted for publication in A&

La construcción de un nuevo Estado y sus políticas públicas : El transporte colectivo urbano en Santiago de Chile, 1925-1957

El 2 de abril de 1957 se registró en Santiago de Chile una de las protesta urbanas de mayor trascendencia, tal conflicto develó tensiones económico-sociales que existían sobre las tarifas, la mantención de los vehículos, las subvenciones del petróleo. Todas estas demandas fueron mediadas por la negociación política del Estado, los empresarios del rubro y los usuarios. El Estado que enfrentó tal situación, se había constituido hacia 1925 distanciándose de la conceptualización liberal clásica, enfatizando un rol interventor, proteccionista y nacionalista. Las nuevas atribuciones del Estado permitieron conformar una nueva institucionalidad, que para el caso del transporte urbano, fue la creación de Empresa Nacional de Transportes Colectivos S.A. (ENT) en 1945 y la Empresa de Transportes Colectivos del Estado (ETC del E) en 1953, empresas que con el rápido crecimiento demográfico y su concentración en la capital, se mostró deficiente e insuficiente en un corto período. Los nuevos grupos de presión en búsqueda de mejor participación en el ingreso nacional, profundizaron la inflación que intensificó los desacuerdos sociales sobre las políticas públicas a implementar, reforzando la crisis integral del país, convirtiendo con ello, en palabras del economista Aníbal Pinto a Chile en un caso de desarrollo frustrado (1958). En relación a lo antes señalado, la presente ponencia tiene por objetivo ayudar en la comprensión del fracaso del sistema público de transporte colectivo de la capital chilena durante el período desarrollista, fracaso que aún en nuestros días, deja severos desencuentros sociales e incide directamente en la vida de millones de santiaguinos.Mesa 18: El Estado como problema y solución: Estado, administración y políticas públicasFacultad de Humanidades y Ciencias de la Educació

Motion and collision of particles near DST Black holes

We consider Deser-Sarioglu-Tekin (DST) black holes as background and we study such the motion of massive particles as the collision of two spinning particles in the vicinity of its horizon. New kinds of orbits are allowed for small deviations of General Relativity, but the behavior of the collision is similar to the one observed for General Relativity. Some observables like bending of light and the perihelion precession are analyzed.Comment: 21 pages and 10 figures. New versio

Characterization and fractionation in Aqueous Two-Phase Systems of site-specific PEGylated antibodies: Targeting stem cell separation

Affinity aqueous-two phase systems (ATPS) are constructed by complementing ATPS with the use of antibodies. This novel methodology represents an attractive alternative for the recovery of stem cells that exhibits several advantages including: biocompatibility, economical attractiveness, scalability, and low processing time. Moreover, the PEGylation of the added antibody with a freely activated site exploiting a site-specific PEGylation via biotin-streptavidin conjugation could confer distinctive characteristics that can be employed in the separation of CD133+ stem cells from human umbilical cord blood samples. Currently, we are performing the site-specific PEGylation of CD133-Biotin antibody with the next six activated biotinylated PEGs: thiol, maleimide, carboxyl, amine, methoxy poly(ethylene glycol), and succinimidyl ester, in order to characterize them and compare their partition behavior utilizing electrophoresis with silver staining and I2-BaCl2 in the following three polymer-polymer aqueous two-phase systems (ATPS): ficoll 400,000-dextran 70,000, PEG 8,000-dextran 500,000, and the novel UCON-dextran 75,000. We hypotethize that the freely activated site may influence the partitioning profile of the PEGylated CD133-Biotin antibody into opposing phases of the contaminants, thus providing a suitable affinity ATPS for the recovery of CD133+ stem cells